MCQ
Q.
Which of the following is not an example of work done?
Correct Answer: A
The correct answer is Boy pushing wall in a room.
Key Points
- Boy pushing the wall in the room is not an example of work done.
- When a boy pushes a wall, he is applying force on the wall. We see that the wall shows no displacement.
- Work is given as the product of the forces and the displacement in the same direction.
- Hence the work done is zero.
Additional Information
- Work is done when a force moves. Everyday examples of work include walking up a flight of stairs, lifting heavy objects, pulling a sled and pushing a shopping trolley, Applying pressure on a pebble lying on the surface, raising a book to a height.
- Work is not done when holding a bag stationary or a book at arm's length because although a force is being applied, the force does not move.
